| Skitch72 |
I think more of a simple math question but I can't seem to get it straight. I am working on the recommended FE126E enclosure which is a hybrid back loaded horn / bass reflex design. Anyway I want to convert the port to english units from millimeters (don't have an 30 mm pipe!)
I know the port is 30mm diameter and 115 mm in length and Fb is 55 Hz
Due to the design I don't know what to include to calculate the enclosure volume.
What would the length need to be to use 1.5" port?
Thanks in advance,
Tim
Here is a link to the design:
http://www.madisound.com/pdf/fostexcabs/fe126e_encl.pdf
:confused: |
|
|
| baggystevo82 |
If you use the ratio 1"=25.4mm that's close enough for most applications. I've started a thread on the enclosure you want to build here, where I think a few of us are considering it:
Fostex FE126E reference design opinions
Feel free to join us and let us know how you get on.
Good luck,
Steve |
|
|
| Skitch72 |
Thanks for the reply and I will keep an eye on that thread to see what others are trying out.
I don't have any issue converting the mm to inches but the port comes out to 1.18" in diameter and 4.5" long. I don't have any material that is that diameter and wondered how to calculate the new length if I change the diameter to 1.5"..
Maybe I'm not making sense...
(wouldn't be the first time)
Tim |
|
|
| GM |
Greets!
Ron E's take on scaling vents:
.........L1/L2 = A1/A2, where L1, A1 are the original length and area, and L2,A2 are the new length and area... rearranging again, and Realizing that area is proportional to diameter squared:
L2 = L1*(D2^2/D1^2), where D2 is new diameter and D1 is the original diameter.
FWIW, *in sims* using MJK's WSs I found that accounting for the end correction difference was more accurate, probably audibly so if a big change in diameter was made, but as always YMMV:
L2 = L1*(D2^2/D1^2)+(D2-D1)^2
GM |
|
|
| Skitch72 |
Thanks! that is exactly what I needed!
Tim
:D |
|
|
|
